Graphics Programs Reference
In-Depth Information
The linear and angular precision settings affect only AutoCAD's
display
of
coordinates, distances, and angles on the status bar, in dialog boxes, and in the
command window and Dynamic Input tooltip areas. For drawings stored as DWG
files, AutoCAD
always
uses maximum precision to store the locations and sizes of
all objects that you draw, regardless of how many decimal places you choose to dis-
play in the Drawing Units dialog box. In addition, AutoCAD provides separate set-
tings for controlling the precision of dimension text — see Chapter 14 for details.
4. Choose an angular unit type from the Angle Type drop-down list.
Decimal Degrees and Deg/Min/Sec are the most common choices.
The Clockwise check box and the Direction button provide additional angle meas-
urement options, but you'll rarely need to change the default settings: Unless you're
a land surveyor, measure angles counterclockwise and use east as the 0-degree dir-
ection.
5. From the Angle Precision drop-down list, choose the degree of precision you
want when AutoCAD displays angular measurements.
6. In the Insertion Scale area, choose the units of measurement for this drawing.
Choose your
base unit
for this drawing — that is, the real-world distance represen-
ted by one AutoCAD unit.
The AutoCAD (but not the AutoCAD LT) Drawing Units dialog box in-
cludes a Lighting area where you specify the unit type to be used to measure the in-
tensity of photometric lights. I introduce lighting as part of rendering 3D models in
Chapter 23.
7. Click OK to exit the dialog box and save your settings.
Making the drawing area snap-py (and grid-dy)
For the last three decades, AutoCAD's
grid
consisted of a set of evenly-spaced dots that
served as a visual distance reference. You can still configure a dot grid in AutoCAD 2012,
but starting with AutoCAD 2011, the default is a snazzy graph-paper-like grid made up of
a network of lines.
AutoCAD's
snap
feature creates a set of evenly spaced, invisible
hot spots,
which make
the crosshairs move in nice, even increments as you specify points in the drawing. Both
Grid Mode and Snap Mode are like the intersection points of the lines on a piece of grid
